IRVINE – Four architectural designers completed a marathon of presentations Friday on the Great Park, offering visions as varied as all outdoors.

Ken Smith of New York would create a canyon in the middle of the park, Hargreaves Associates suggested a canal walk, EMBT Arquitectes presented an imaginative terrain and Ábalos & Herreros would like to fill a long runway excavation with water for a rowing site.

But many questions remain. Among them: How much will the park cost to create? How long will it take to finish? And, will people embrace the park in the manner of a Central Park in New York?

Only one firm included cost estimates on building the public portions of the park.

Several of the designers rearranged the acreage they had to work with, but the company that won the contract to build the privately owned portions of the park – Lennar Corp. – has said it is open to change.

Project summary: Smith put together perhaps the most comprehensive team, and his proposal was among the most thorough. The plan features “outdoor rooms,” areas delineated by hedges, trees or other natural features, which can be gathering places for events and cultural activities. Areas include woodlands, meadows and tree-lined streams. The plan includes 50 vintage military aircraft set along segments of the old runways.

Highlights:

• A 30-foot-deep canyon in the center, with the excavated earth used to form 30-foot berms on each side, thus giving visitors the sense of a 60-foot-deep canyon.

• Embedded buildings, some with earth covering the tops to save energy.

• Two shuttle systems making continuous loops around the park.

Comments from the board:

• “This is the dream park as far as I am concerned.” – Steven Choi.

• Christina Shea called the plan exciting and said she particularly liked the amphitheater.

• Michael Pinto questioned whether enough naturally flowing water would be available for the wetlands in the plan.

Hargreaves Associates

Based: San Francisco

Project summary

This plan features a canal walk along a section of an old runway. The runway excavation is filled with water from two streams that would cut through the base. The plan uses some of the old hangars as centers for cultural activities. More conceptual than specific, this plan envisions ongoing discussions about particular uses.

Highlights

• Visitors could walk up stairways and platforms for a view of the park.

• Some athletic fields are intertwined with the park’s open spaces.

• Use of synthetic turf is suggested for intensively used fields.

Comments from the board

• Sukhee Kang wanted more details on how the hangars would be converted to civilian use.

• Michael Pinto wondered what the main attraction was; answer: “It’s about many things – water, nature, athletics and culture.”

EMBT Arquitectes Associats

Based: Barcelona, Spain

Project summary

EMBT was one of the few finalists whose design does not integrate the linear shape and direction of the runways into its concept. Rather, the abstract project is designed in layers around a central “Great Lake.” During the presentation, principals from EMBT stressed the importance of collaborating with the board and the community to create the final design.

Highlights

• A Great Lake that lends itself to a variety of activities; EMBT also included comprehensive engineering plans to show how the lake would be naturally replenished.

• The majority of development is focused on the southern edge of the park; intended to “finish the city” and lead visitors into nature.

• Parking structures on the southern border are covered with earth and are intended to become part of the landscape.

Comments from the board

• Michael Ray called the plan “brilliant.” He complimented the group on its engineering plans.

• Choi was concerned that a tribute to the park’s military history was not more obvious.

• “I’m overwhelmed by the creativity of your firm,” Shea said.

Ábalos & Herreros ArquitectosBased: Madrid, Spain

Project summary

Considered one of the more futuristic concept designs, this team focused its design around an Olympic-sized rowing canal. The project also includes an aerial tramway to move visitors around the park. By utilizing solar power and storing water in the canal, this design would be 95.percent sustainable.Highlights

• The 1.24-mile canal would not only act as a sports attraction but would also be a reservoir to hold enough water to support the park’s landscaping needs.

• Four observatories throughout the park would offer visitors glimpses into art, history, renewable energy and nature.

• A circuit loop around the park would cater to runners, cyclists and horses.

Comments from the board

• Beth Krom called the plan “incredibly visionary” and said it was “the most intense representation” of a 21st century park.

• More than one board member questioned the cost of building the canal and aerial tram.Santa Ana Mayor Miguel Pulido said, “You’re pushing the envelope, and that’s what we want to see.”

THURSDAY’S PRESENTATIONS:

OLIN PARTNERSHIPS LTD.

Based:Philadelphia

Project summary:The geometrical design offers circles, spirals and linear angles to create its park concept. Most of the development is focused in two areas on the park’s periphery; the majority of the park is open space, which cuts development costs. At the center of the park is a marsh overlooked by four “earth platforms,” elevated walking trails that follow the park’s natural slope and are designed to add depth to an otherwise flat park.

Highlights

• A main boulevard encircles the park, creating a border between the private development and the public park. The 4.6-mile boulevard is designed to attract walkers and bikers. Cars also could use it, but visitors would be encouraged to use a shuttle system between four stops.

• Four waterways converge in a manmade marsh at the park’s center, which is designed to be a way station for migrating birds.

Comments from the board

• Board member Michael Pinto called the design “bold and dramatic.”

• Board member Steven Choi asked whether developer Lennar would be willing to work around the manipulations to the border required to form a perfect circle.

• Board member Christina Shea said there might be too much undeveloped land and that she did not envision such a passive use (the marsh) at the center of the park.

RICHARD HAAG ASSOCIATES

Based: Seattle

Project summary:The Blue/Green Park, as Haag’s team named this design, is structured over the former runways, which would remain intact. At the center of the park is a “Great Knoll” which would be created with soil dug up while creating the nearby “Great Lake.” Unlike any other design, Haag’s included some residential development in the park.

Highlights

• The Great Knoll and 30-acre Great Lake act as a yin and yang core to the park. A “continuous arboretum” weaves throughout the park and around the knoll and lake.

• Park visitors would be shuttled around in an electric bus, which would run partially on solar power.

• By using the runways rather than demolishing them, the development timeline is accelerated.

Comments from the board

• Nearly all the board members expressed disdain for including residential development inside the park’s boundaries.

• If the runways are preserved, developers would have to come up with another way to create the roads and curbs, which were planned to be made with the crushed concrete.

ROYSTON HANAMOTO ALLEY & ABEY

Based:Mill Valley

Project summary:Orientation of the gardens, groves of trees, trails and other features follows the main, crossing runway paths, tracing “the memory of what was here before.” The plan makes the most innovative use of several of the old hangars, transforming them into activity centers and adding new exterior walls that allow light to enter.

Highlights

• The five entryways all are very different: One is planted in palm trees, one with ficus trees, another with oaks.

• Geothermal energy would be tapped from deep wells; solar energy would power shuttle buses.

• Parking lots are on the perimeter, access to the center is by shuttle buses, electric carts or free bicycles are checked out like library books.

Comments from the board

• Board member Miguel Pulido wondered how adaptable the solar-electricity panels would be to upgrade as new technology becomes available.

• Board member Walkie Ray wondered how the park might be made more visually appealing from the Santa Ana (I-5) Freeway.